With the increasing popularity of new energy vehicles, the use of power batteries in new energy vehicles is becoming more and more demanding. Especially, a requirement of a user for endurance mileage of the new energy vehicle continuously increases. The total capacity of a battery pack used by the new energy vehicle needs to be continuously improved. In addition, in a use process of the power battery pack, internal consumption and heating caused by an internal resistance are required to be minimized.
Generally, only one nude battery core or a plurality of nude battery cores connected in parallel is disposed in a case of the battery, and a single nude battery core or a plurality of nude battery cores connected in parallel cannot improve the voltage of the whole battery. For example, a voltage of a lithium titanate battery is 2.4V; a voltage of a lithium iron phosphate battery is 3.2V; a voltage of a ternary battery is 3.7V; and a voltage of a multi-polymer battery is 4.3V. Therefore, when a high voltage (a high capacity) is required, a large quantity of batteries is connected in series to form a battery group, and then battery groups are assembled into a power battery pack. Two adjacent battery need to be connected through a connector to perform a power connection. Consequently, there are many battery installation structures, which not only increase costs but also increase an entire weight. In addition, the installation structures occupy relatively large internal space of the pack, leading to a reduction in an overall capacity of the power battery pack. The more batteries are disposed side by side, the more space is wasted. In addition, because a plurality of peripheral power connector needs to be disposed to form a power connection, the internal resistance is increased, thus increasing internal consumption and heating of the power battery pack during use.